LED updates for 5.1-rc1

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Merge tag 'leds-for-5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds

Pull LED updates from Jacek Anaszewski:

 - finalize previously announced support for initialization of pattern
   triggers from Device Tree

 - fix for null deref on firmware load failure in leds-lp55xx-common.c

* tag 'leds-for-5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
  leds: lp55xx: fix null deref on firmware load failure
  leds: trigger: timer: Add initialization from Device Tree
  leds: trigger: oneshot: Add initialization from Device Tree
  leds: trigger: pattern: Add pattern initialization from Device Tree
  leds: Add helper for getting default pattern from Device Tree
  dt-bindings: leds: Add pattern initialization from Device Tree

Documentation/ABI/testing/sysfs-class-led-trigger-pattern

@@ -7,55 +7,10 @@ Description:
 		timer. It can do gradual dimming and step change of brightness.
 
 		The pattern is given by a series of tuples, of brightness and
-		duration (ms). The LED is expected to traverse the series and
-		each brightness value for the specified duration. Duration of
-		0 means brightness should immediately change to new value, and
-		writing malformed pattern deactivates any active one.
+		duration (ms).
 
-		1. For gradual dimming, the dimming interval now is set as 50
-		milliseconds. So the tuple with duration less than dimming
-		interval (50ms) is treated as a step change of brightness,
-		i.e. the subsequent brightness will be applied without adding
-		intervening dimming intervals.
-
-		The gradual dimming format of the software pattern values should be:
-		"brightness_1 duration_1 brightness_2 duration_2 brightness_3
-		duration_3 ...". For example:
-
-		echo 0 1000 255 2000 > pattern
-
-		It will make the LED go gradually from zero-intensity to max (255)
-		intensity in 1000 milliseconds, then back to zero intensity in 2000
-		milliseconds:
-
-		LED brightness
-		    ^
-		255-|       / \            / \            /
-		    |      /    \         /    \         /
-		    |     /       \      /       \      /
-		    |    /          \   /          \   /
-		  0-|   /             \/             \/
-		    +---0----1----2----3----4----5----6------------> time (s)
-
-		2. To make the LED go instantly from one brightness value to another,
-		we should use zero-time lengths (the brightness must be same as
-		the previous tuple's). So the format should be:
-		"brightness_1 duration_1 brightness_1 0 brightness_2 duration_2
-		brightness_2 0 ...". For example:
-
-		echo 0 1000 0 0 255 2000 255 0 > pattern
-
-		It will make the LED stay off for one second, then stay at max brightness
-		for two seconds:
-
-		LED brightness
-		    ^
-		255-|        +---------+    +---------+
-		    |        |         |    |         |
-		    |        |         |    |         |
-		    |        |         |    |         |
-		  0-|   -----+         +----+         +----
-		    +---0----1----2----3----4----5----6------------> time (s)
+		The exact format is described in:
+		Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
 
 What:		/sys/class/leds/<led>/hw_pattern
 Date:		September 2018

Documentation/devicetree/bindings/leds/common.txt

@@ -37,6 +37,18 @@ Optional properties for child nodes:
      "ide-disk" - LED indicates IDE disk activity (deprecated),
                   in new implementations use "disk-activity"
      "timer" - LED flashes at a fixed, configurable rate
+     "pattern" - LED alters the brightness for the specified duration with one
+                 software timer (requires "led-pattern" property)
+
+- led-pattern : Array of integers with default pattern for certain triggers.
+                Each trigger may parse this property differently:
+                - one-shot : two numbers specifying delay on and delay off (in ms),
+                - timer : two numbers specifying delay on and delay off (in ms),
+                - pattern : the pattern is given by a series of tuples, of
+                  brightness and duration (in ms).  The exact format is
+                  described in:
+                  Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
+
 
 - led-max-microamp : Maximum LED supply current in microamperes. This property
                      can be made mandatory for the board configurations

Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt

@@ -0,0 +1,49 @@
+* Pattern format for LED pattern trigger
+
+The pattern is given by a series of tuples, of brightness and duration (ms).
+The LED is expected to traverse the series and each brightness value for the
+specified duration. Duration of 0 means brightness should immediately change to
+new value, and writing malformed pattern deactivates any active one.
+
+1. For gradual dimming, the dimming interval now is set as 50 milliseconds. So
+the tuple with duration less than dimming interval (50ms) is treated as a step
+change of brightness, i.e. the subsequent brightness will be applied without
+adding intervening dimming intervals.
+
+The gradual dimming format of the software pattern values should be:
+"brightness_1 duration_1 brightness_2 duration_2 brightness_3 duration_3 ...".
+For example (using sysfs interface):
+
+echo 0 1000 255 2000 > pattern
+
+It will make the LED go gradually from zero-intensity to max (255) intensity in
+1000 milliseconds, then back to zero intensity in 2000 milliseconds:
+
+LED brightness
+    ^
+255-|       / \            / \            /
+    |      /    \         /    \         /
+    |     /       \      /       \      /
+    |    /          \   /          \   /
+  0-|   /             \/             \/
+    +---0----1----2----3----4----5----6------------> time (s)
+
+2. To make the LED go instantly from one brightness value to another, we should
+use zero-time lengths (the brightness must be same as the previous tuple's). So
+the format should be: "brightness_1 duration_1 brightness_1 0 brightness_2
+duration_2 brightness_2 0 ...".
+For example (using sysfs interface):
+
+echo 0 1000 0 0 255 2000 255 0 > pattern
+
+It will make the LED stay off for one second, then stay at max brightness for
+two seconds:
+
+LED brightness
+    ^
+255-|        +---------+    +---------+
+    |        |         |    |         |
+    |        |         |    |         |
+    |        |         |    |         |
+  0-|   -----+         +----+         +----
+    +---0----1----2----3----4----5----6------------> time (s)

drivers/leds/led-core.c

@@ -16,7 +16,9 @@
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/of.h>
 #include <linux/rwsem.h>
+#include <linux/slab.h>
 #include "leds.h"
 
 DECLARE_RWSEM(leds_list_lock);
@@ -310,6 +312,34 @@ int led_update_brightness(struct led_classdev *led_cdev)
 }
 EXPORT_SYMBOL_GPL(led_update_brightness);
 
+u32 *led_get_default_pattern(struct led_classdev *led_cdev, unsigned int *size)
+{
+	struct device_node *np = dev_of_node(led_cdev->dev);
+	u32 *pattern;
+	int count;
+
+	if (!np)
+		return NULL;
+
+	count = of_property_count_u32_elems(np, "led-pattern");
+	if (count < 0)
+		return NULL;
+
+	pattern = kcalloc(count, sizeof(*pattern), GFP_KERNEL);
+	if (!pattern)
+		return NULL;
+
+	if (of_property_read_u32_array(np, "led-pattern", pattern, count)) {
+		kfree(pattern);
+		return NULL;
+	}
+
+	*size = count;
+
+	return pattern;
+}
+EXPORT_SYMBOL_GPL(led_get_default_pattern);
+
 /* Caller must ensure led_cdev->led_access held */
 void led_sysfs_disable(struct led_classdev *led_cdev)
 {

drivers/leds/leds-lp55xx-common.c

@@ -201,7 +201,7 @@ static void lp55xx_firmware_loaded(const struct firmware *fw, void *context)
 
 	if (!fw) {
 		dev_err(dev, "firmware request failed\n");
-		goto out;
+		return;
 	}
 
 	/* handling firmware data is chip dependent */
@@ -214,9 +214,9 @@ static void lp55xx_firmware_loaded(const struct firmware *fw, void *context)
 
 	mutex_unlock(&chip->lock);
 
-out:
 	/* firmware should be released for other channel use */
 	release_firmware(chip->fw);
+	chip->fw = NULL;
 }
 
 static int lp55xx_request_firmware(struct lp55xx_chip *chip)

drivers/leds/trigger/ledtrig-oneshot.c

@@ -130,6 +130,34 @@ static struct attribute *oneshot_trig_attrs[] = {
 };
 ATTRIBUTE_GROUPS(oneshot_trig);
 
+static void pattern_init(struct led_classdev *led_cdev)
+{
+	u32 *pattern;
+	unsigned int size = 0;
+
+	pattern = led_get_default_pattern(led_cdev, &size);
+	if (!pattern)
+		goto out_default;
+
+	if (size != 2) {
+		dev_warn(led_cdev->dev,
+			 "Expected 2 but got %u values for delays pattern\n",
+			 size);
+		goto out_default;
+	}
+
+	led_cdev->blink_delay_on = pattern[0];
+	led_cdev->blink_delay_off = pattern[1];
+	kfree(pattern);
+
+	return;
+
+out_default:
+	kfree(pattern);
+	led_cdev->blink_delay_on = DEFAULT_DELAY;
+	led_cdev->blink_delay_off = DEFAULT_DELAY;
+}
+
 static int oneshot_trig_activate(struct led_classdev *led_cdev)
 {
 	struct oneshot_trig_data *oneshot_data;
@@ -140,8 +168,14 @@ static int oneshot_trig_activate(struct led_classdev *led_cdev)
 
 	led_set_trigger_data(led_cdev, oneshot_data);
 
-	led_cdev->blink_delay_on = DEFAULT_DELAY;
-	led_cdev->blink_delay_off = DEFAULT_DELAY;
+	if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) {
+		pattern_init(led_cdev);
+		/*
+		 * Mark as initialized even on pattern_init() error because
+		 * any consecutive call to it would produce the same error.
+		 */
+		led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
+	}
 
 	return 0;
 }

drivers/leds/trigger/ledtrig-pattern.c

@@ -220,12 +220,48 @@ out:
 	return count;
 }
 
+static int pattern_trig_store_patterns_string(struct pattern_trig_data *data,
+					      const char *buf, size_t count)
+{
+	int ccount, cr, offset = 0;
+
+	while (offset < count - 1 && data->npatterns < MAX_PATTERNS) {
+		cr = 0;
+		ccount = sscanf(buf + offset, "%d %u %n",
+				&data->patterns[data->npatterns].brightness,
+				&data->patterns[data->npatterns].delta_t, &cr);
+		if (ccount != 2) {
+			data->npatterns = 0;
+			return -EINVAL;
+		}
+
+		offset += cr;
+		data->npatterns++;
+	}
+
+	return 0;
+}
+
+static int pattern_trig_store_patterns_int(struct pattern_trig_data *data,
+					   const u32 *buf, size_t count)
+{
+	unsigned int i;
+
+	for (i = 0; i < count; i += 2) {
+		data->patterns[data->npatterns].brightness = buf[i];
+		data->patterns[data->npatterns].delta_t = buf[i + 1];
+		data->npatterns++;
+	}
+
+	return 0;
+}
+
 static ssize_t pattern_trig_store_patterns(struct led_classdev *led_cdev,
-					   const char *buf, size_t count,
-					   bool hw_pattern)
+					   const char *buf, const u32 *buf_int,
+					   size_t count, bool hw_pattern)
 {
 	struct pattern_trig_data *data = led_cdev->trigger_data;
-	int ccount, cr, offset = 0, err = 0;
+	int err = 0;
 
 	mutex_lock(&data->lock);
 
@@ -237,20 +273,12 @@ static ssize_t pattern_trig_store_patterns(struct led_classdev *led_cdev,
 	data->is_hw_pattern = hw_pattern;
 	data->npatterns = 0;
 
-	while (offset < count - 1 && data->npatterns < MAX_PATTERNS) {
-		cr = 0;
-		ccount = sscanf(buf + offset, "%d %u %n",
-				&data->patterns[data->npatterns].brightness,
-				&data->patterns[data->npatterns].delta_t, &cr);
-		if (ccount != 2) {
-			data->npatterns = 0;
-			err = -EINVAL;
-			goto out;
-		}
-
-		offset += cr;
-		data->npatterns++;
-	}
+	if (buf)
+		err = pattern_trig_store_patterns_string(data, buf, count);
+	else
+		err = pattern_trig_store_patterns_int(data, buf_int, count);
+	if (err)
+		goto out;
 
 	err = pattern_trig_start_pattern(led_cdev);
 	if (err)
@@ -275,7 +303,7 @@ static ssize_t pattern_store(struct device *dev, struct device_attribute *attr,
 {
 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
 
-	return pattern_trig_store_patterns(led_cdev, buf, count, false);
+	return pattern_trig_store_patterns(led_cdev, buf, NULL, count, false);
 }
 
 static DEVICE_ATTR_RW(pattern);
@@ -295,7 +323,7 @@ static ssize_t hw_pattern_store(struct device *dev,
 {
 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
 
-	return pattern_trig_store_patterns(led_cdev, buf, count, true);
+	return pattern_trig_store_patterns(led_cdev, buf, NULL, count, true);
 }
 
 static DEVICE_ATTR_RW(hw_pattern);
@@ -331,6 +359,30 @@ static const struct attribute_group *pattern_trig_groups[] = {
 	NULL,
 };
 
+static void pattern_init(struct led_classdev *led_cdev)
+{
+	unsigned int size = 0;
+	u32 *pattern;
+	int err;
+
+	pattern = led_get_default_pattern(led_cdev, &size);
+	if (!pattern)
+		return;
+
+	if (size % 2) {
+		dev_warn(led_cdev->dev, "Expected pattern of tuples\n");
+		goto out;
+	}
+
+	err = pattern_trig_store_patterns(led_cdev, NULL, pattern, size, false);
+	if (err < 0)
+		dev_warn(led_cdev->dev,
+			 "Pattern initialization failed with error %d\n", err);
+
+out:
+	kfree(pattern);
+}
+
 static int pattern_trig_activate(struct led_classdev *led_cdev)
 {
 	struct pattern_trig_data *data;
@@ -354,6 +406,15 @@ static int pattern_trig_activate(struct led_classdev *led_cdev)
 	timer_setup(&data->timer, pattern_trig_timer_function, 0);
 	led_cdev->activated = true;
 
+	if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) {
+		pattern_init(led_cdev);
+		/*
+		 * Mark as initialized even on pattern_init() error because
+		 * any consecutive call to it would produce the same error.
+		 */
+		led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
+	}
+
 	return 0;
 }
 

drivers/leds/trigger/ledtrig-timer.c

@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/ctype.h>
+#include <linux/slab.h>
 #include <linux/leds.h>
 
 static ssize_t led_delay_on_show(struct device *dev,
@@ -77,8 +78,41 @@ static struct attribute *timer_trig_attrs[] = {
 };
 ATTRIBUTE_GROUPS(timer_trig);
 
+static void pattern_init(struct led_classdev *led_cdev)
+{
+	u32 *pattern;
+	unsigned int size = 0;
+
+	pattern = led_get_default_pattern(led_cdev, &size);
+	if (!pattern)
+		return;
+
+	if (size != 2) {
+		dev_warn(led_cdev->dev,
+			 "Expected 2 but got %u values for delays pattern\n",
+			 size);
+		goto out;
+	}
+
+	led_cdev->blink_delay_on = pattern[0];
+	led_cdev->blink_delay_off = pattern[1];
+	/* led_blink_set() called by caller */
+
+out:
+	kfree(pattern);
+}
+
 static int timer_trig_activate(struct led_classdev *led_cdev)
 {
+	if (led_cdev->flags & LED_INIT_DEFAULT_TRIGGER) {
+		pattern_init(led_cdev);
+		/*
+		 * Mark as initialized even on pattern_init() error because
+		 * any consecutive call to it would produce the same error.
+		 */
+		led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
+	}
+
 	led_blink_set(led_cdev, &led_cdev->blink_delay_on,
 		      &led_cdev->blink_delay_off);
 

include/linux/leds.h

@@ -218,6 +218,19 @@ extern int led_set_brightness_sync(struct led_classdev *led_cdev,
  */
 extern int led_update_brightness(struct led_classdev *led_cdev);
 
+/**
+ * led_get_default_pattern - return default pattern
+ *
+ * @led_cdev: the LED to get default pattern for
+ * @size:     pointer for storing the number of elements in returned array,
+ *            modified only if return != NULL
+ *
+ * Return:    Allocated array of integers with default pattern from device tree
+ *            or NULL.  Caller is responsible for kfree().
+ */
+extern u32 *led_get_default_pattern(struct led_classdev *led_cdev,
+				    unsigned int *size);
+
 /**
  * led_sysfs_disable - disable LED sysfs interface
  * @led_cdev: the LED to set